One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,7,8,6)(12,20)(15,22)(18,24)(21,23)(25,26)(27,32)(28,33)(29,35)(30,34)(31,36)(37,39)(38,40)(2,3)(6,7)(9,10,13,16)(11,14,19,17)(12,15,20,22)(18,21,24,23)(25,27,31,33)(26,32,36,28)(29,37,30,38)(34,40,35,39)(1,3,5,2)(4,7,8,6)(9,10)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,27)(26,28)(29,37)(30,38)(31,33)(32,36)(34,39)(35,40)(1,4,5,8)(2,6,3,7)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(25,28)(26,33)(27,36)(29,39)(30,40)(31,32)(34,38)(35,37)(25,29,31,30)(26,34,36,35)(27,37,33,38)(28,39,32,40)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,30,31,29)(26,35,36,34)(27,38,33,37)(28,40,32,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.